South American pemphigus foliaceus: electron microscopy and immunoelectron localization of bound immunoglobulin in the skin and oral mucosa.

Five skin and two oral biopsies from patients with South American pemphigus foliaceus (SAPF) were studied by electron and immunoelectron microscopy for the ultrastructural localization of bound immunoglobulin in epidermal and oral lesions. Electron microscopy showed the tonofilament-desmosome complex to be preserved in the various layers of the epidermis. Immunoglobulin was bound over the plasma membrane and permeated the desmosomal junctions both in the skin and oral mucosa, thus suggesting that pemphigus antibodies are attached to the glycocalyx. It appears that the initial injury in SAPF acantholysis involves the glycocalyx and that it might be caused by interaction with intercellular antibodies present in the patient's serum.